The present invention relates to stick-type cosmetic compositions, in particular, solid stick deodorant compositions. More specifically, the present invention relates to a deodorant composition containing a base of a polyhydric (e.g., propylene glycol) and/or monohydric (e.g., ethanol) alcohol, together with water, gelled with alkali metal salts of saturated fatty acids, having improved clarity and appearance. In particular, the present invention relates to clear deodorant compositions containing propylene glycol and water, as the base, and gelled with sodium salts of saturated fatty acids having a carbon length of 12-22 (that is, sodium salts of relatively long carbon chain length fatty acids), having improved clarity and appearance without crystal formation (that is, wherein the composition does not form crystals over a period of time after formation of the composition).
It has been desired to provide clear cosmetic stick compositions (for example, clear deodorant solid stick compositions) having a composition base of a polyhydric alcohol (e.g., a glycol such as propylene glycol) and/or a monohydric alcohol (e.g., ethanol), together with water, gelled with, e.g., sodium salts of saturated fatty acids, wherein crystal formation after forming of the composition is reduced (thereby to improve clarity of the composition and appearance of the product). This problem of crystal formation, and reduced clarity and appearance of the product, is especially acute where the alkali metal salts (e.g., sodium salts) of saturated fatty acids include those with relatively long carbon chain lengths of the fatty acid (for example, a carbon chain length up to C.sub.22). Use of such relatively long carbon chain length fatty acids is desired in that they provide a product having a relatively high melting temperature and, correspondingly, relatively greater stability.
U.S. Pat. No. 4,382,079 to Marschner discloses a deodorant cosmetic stick consisting essentially of at least about 0.1-3% and up to about 70% of an alkali metal bicarbonate, and about 0.10% suspending agent, dispersed in a soap-based gel which comprises a major amount of an aqueous or anhydrous polyhydric alcohol or a mixture of a polyhydric alcohol and monohydric alcohol, gelled by a minor amount of an alkali metal salt of a fatty acid containing 14 to 20 carbon atoms. This patent discloses that the sodium or potassium soap-based gel into which the aqueous bicarbonate solution or suspension is incorporated includes a polyhydric alcohol or a mixture of a polyhydric and monohydric alcohol, suitable polyhydric alcohols including glycerin and the lower alkylene glycols of low molecular weight which are liquid at room temperature, such as ethylene glycol, diethylene glycol, butylene glycol and preferably propylene glycol. This patent further discloses that any type of high molecular weight saturated fatty acid may be used as the fatty acid for the alkali metal (e.g., sodium or potassium) salt utilized as the gelling agent, although it is preferred to employ commercial stearic acid which includes essentially a mixture of stearic and palmitic acids (C.sub.16 and C.sub.18 acids).
Although disclosing soap-based stick deodorant compositions wherein the gelling agents, of alkali metal salts of saturated fatty acids, utilize fatty acids with a carbon chain length up to 20, this patent does not disclose any crystallization problems occurring, which can effect clarity and appearance of the final product. In fact, this patent is primarily concerned with incorporation of bicarbonate in the stick, and discloses that the transparency of the bicarbonate stick is reduced as the solubility of the bicarbonate in the soap gel is reduced. Moreover, this patent discloses that preferably sodium salts of commercial stearic acid (containing relatively short carbon chain stearic and palmitic acids) are utilized as the gelling agent. Thus, this patent, in particular, does not address the acute problem of crystal formation occurring in sticks based on alcoholic soap gels gelled with, e.g., sodium salts of saturated fatty acids having a relatively long carbon chain length, up to and beyond C.sub.22.
U.S. Pat. No. 4,322,400 to Yuhas discloses stick-type cosmetic compositions. The compositions contain, as a basic vehicle, a mixture of water and sodium stearate in proportions sufficient to form a self-supporting solid composition which does not readily deform, and yet is not so firm that a hard, waxy composition results which will not leave a deposit of the active ingredient on skin to which the composition is applied. The composition described in this patent further includes (in addition to the active ingredient, water and sodium stearate) water-compatible polyhydroxyl compounds such as glycerin, a glycol or a polyglycol, to modify the physical properties of the composition and impart an improved "feel", and relatively small amounts of sodium chloride. The sodium chloride is added in order to prevent "syneresis" (that is, exuding of water from the solid stick), at temperature extremes of 0.degree.-40.degree. C. or more than 50.degree. C. This patent discloses that the addition of the relatively small amounts of sodium chloride also increases the settling point, as well as the rate of setting, of the water-sodium stearate cosmetic stick base. This patent further discloses that the sodium chloride can be employed in an amount of at least about 0.5 weight %, and preferably at least about 1 weight %, and up to about 5 weight %, based upon the water-sodium stearate vehicle.
U.S. Pat. No. 4,322,400 is primarily concerned with incorporation of sodium chloride into sodium stearate-gelled water-based compositions, and does not further define the gelling agent apart from disclosing use of "sodium stearate". This patent does not disclose crystallization problems, particularly such problems when relatively long carbon chain fatty acids are utilized in the gelling agent, and only discloses that sodium chloride is included to avoid "syneresis" problems and achieve increased settling point and rate of setting (that is, this patent does not disclose incorporating sodium chloride in the cosmetic stick composition to avoid crystallization problems).
U.S. Pat. No. 4,725,432 to May discloses solid stick compositions, based upon waxy materials of long-chain fatty alcohols in combination with volatile silicones, such compositions also containing an alcohol selected from the group consisting of (1) C.sub.20 alcohols, (2) those alcohols whose chains are longer than C.sub.20, and (3) mixtures of (1) and (2), at levels of from about 1% to about 3% of the total long-chain fatty alcohols present in the compositions. This patent further discloses that the long-chain fatty alcohols forming the base of the composition are those having melting points of from about 100.degree. F. to about 150.degree. F., these including fatty alcohols containing from about 8 to about 18 carbon atoms in their chains, suitable examples including cetyl alcohol, stearyl alcohol, myristyl alcohol, lauryl alcohol and mixtures thereof.
U.S. Pat. No. 4,725,432 is not a water or alcohol/water-based stick composition gelled with alkali metal salts of saturated fatty acids. Moreover, this patent does not disclose clear compositions; and does not teach the problem of crystal formation in deodorant compositions having a base of alcohol and water gelled with alkali metal salts of saturated fatty acids, or the particularly acute problem of crystal formation occurring when the gelling agent includes relatively long-length carbon chain fatty acids.
As seen in the foregoing, the references do not address the problem of crystal formation, which reduces clarity and appearance of the solid stick composition including a base of alcohol and water, gelled with alkali metal salts of saturated fatty acids; or the particularly acute problem of crystal formation occurring where the saturated fatty acids have a relatively long carbon chain length up to and beyond C.sub.22. Moreover, the compositions disclosed in these references do not inherently solve this problem. Accordingly, it is still desired to provide a cosmetic stick composition (e.g., a clear deodorant solid stick composition) having a base of polyhydric and/or monohydric alcohol and water, gelled with alkali metal salts of saturated fatty acids, avoiding crystal formation of such composition and its associated reduction of clarity and appearance of the product.